PWC for high nitrites during cycle?

Rangerbob86 · May 16, 2015

I realize there are already quite a few threads on this topic and that Iâ€™m probably going to get split opinions, but I thought Iâ€™d try anyways. My 20 gallon long tank has been cycling for just over 6 weeks now. Tank has a heater, airstone, and Aquaclear 70 HOB filer. All were purchased brand new. The HOB filter has one sponge and one bag of biomax in it (not running the carbon). I started the cycle with a bottle of Dr. Tims One and Only and dosed about 3 - 4 ppm Ace Hardware brand ammonia. After about a week there was no more ammonia so I dosed it back up to 3 - 4 ppm. Ever since then, nitrites have been very high (off the API chart). I continued to dose ammonia to about 2 ppm every few days. Last week, I did my first water change (about 50%) in an effort to bring down the nitrites but didnâ€™t see any results. Here are my parameters today:

API Test:
Ammonia: 0
Nitrite: > 5 ppm
Nitrate: 80 to 160 ppm
pH: 8.0
Salinity: 1.025
Temp: 79

Seachem Nitrite/Nitrate Test:
Nitrite: 10 to 25 ppm
Nitrate: > 50 ppm

At this point Iâ€™m not sure if I should do another water change or give it more time. Should I continue to dose the ammonia? 2 ppm ammonia is being processed in 24 hours. Should I put another sponge/more biomax in the filter in place of the carbon? Any help would be appreciated!

Squid · May 16, 2015

Rangerbob86 said:
I realize there are already quite a few threads on this topic and that Iâ€™m probably going to get split opinions, but I thought Iâ€™d try anyways. My 20 gallon long tank has been cycling for just over 6 weeks now. Tank has a heater, airstone, and Aquaclear 70 HOB filer. All were purchased brand new. The HOB filter has one sponge and one bag of biomax in it (not running the carbon). I started the cycle with a bottle of Dr. Tims One and Only and dosed about 3 - 4 ppm Ace Hardware brand ammonia. After about a week there was no more ammonia so I dosed it back up to 3 - 4 ppm. Ever since then, nitrites have been very high (off the API chart). I continued to dose ammonia to about 2 ppm every few days. Last week, I did my first water change (about 50%) in an effort to bring down the nitrites but didnâ€™t see any results. Here are my parameters today:

API Test:
Ammonia: 0
Nitrite: > 5 ppm
Nitrate: 80 to 160 ppm
pH: 8.0
Salinity: 1.025
Temp: 79

Seachem Nitrite/Nitrate Test:
Nitrite: 10 to 25 ppm
Nitrate: > 50 ppm

At this point Iâ€™m not sure if I should do another water change or give it more time. Should I continue to dose the ammonia? 2 ppm ammonia is being processed in 24 hours. Should I put another sponge/more biomax in the filter in place of the carbon? Any help would be appreciated!

Stop dosing ammonia and stop doing water changes. All your doing is making the cycle process longer, when It would have already been completed about a week ago. Your nitrites are high because you keep dosing ammonia which in turn becomes nitrite and then nitrate. Again stop dosing and wait until your nitrite is 0. Your nitrate will then increase lettng you know the cycle is complete. Do a couple water changes and your good to go.

Randy Holmes-Farley · May 18, 2015

FWIW, the nitrate may not be as high as the kit says, since in some nitrate kits, a small amount of nitrite shows as a lot of nitrate.

I'd just sit back and wait, as suggested above.

pdiehm · May 20, 2015

Squid said:
Stop dosing ammonia and stop doing water changes. All your doing is making the cycle process longer, when It would have already been completed about a week ago. Your nitrites are high because you keep dosing ammonia which in turn becomes nitrite and then nitrate. Again stop dosing and wait until your nitrite is 0. Your nitrate will then increase lettng you know the cycle is complete. Do a couple water changes and your good to go.

I don't know that I would say his cycle would be completed a week ago.

For example. On my tank, I have an Aquaclear 70 (with the media and sponge from an old Aquaclear 20 in addition to the 70 media) and a piece of pukani rock on my 20 gallon QT tank that I'm cycling.

I haven't dosed ammonia in over 7 weeks. My nitrites have never fallen below 1ppm (per red sea test kit). Ammonia tests at 0, and nitrates are through the roof. pH is at roughly 8.3 given that the color purple doesn't match anything on the chart.

I agree that sitting back and waiting is the right call. However it's hard to tell anyone when their cycle would be completed. No one would have ever thought that my QT tank would still be showing nitrites 12 weeks after starting the cycle...and I even dropped a bottle of Dr. Tims nitrifying bacteria in there (which didn't help at all btw).

I am very very close to pulling the media from the tank, letting it dry out, and starting the cycle process all over because I did listen to someone on either this forum or another who said I needed to dose 2ppm ammonia for 4 or 5 consecutive days. Problem is, my biological hasn't ever caught up to that.

Rangerbob86 · Jun 1, 2015

Just wanted to give a quick update...it's been over 2 weeks now since I've stopped dosing ammonia, but no noticeable change in nitrite level. It's been just over 8 weeks total for the cycle now. Continue waiting? Or is there something else I can be doing? Thanks!